Time has come for a few new reloading posts...I have recently become aware of a problem with my quality control related to case sizing.
I was boxing up some 55 gr Hornady SPP loads, and decided to case gauge them as I went.
My findings were not good.
Many of the lot of 200 were too long in the headspace area. I surmised the problem had been a loose die that had backed out a few thousandth of an inch and I failed to check it.
Since I only bump the shoulders back about .003", I wanted a way to test the cartridges in an exact way, so I put in an order to Midway for a Hornady Lock-N-Load Headspace Gage Set with Comparator.
.
This tool makes it possible to set the shoulder bump exactly, and to measure the results. Different brass appears to react differently, especially if your lubing technique is inconsistent.
I found, using the comparator gauge, that many cases were .003" longer than the fireformed brass I was using as a zero point. That means a big jam, or not going all the way into battery...not a good thing.
Now I have concluded that I need a special die called a BODY die that only re-sizes a case body and shoulder without resizing or otherwise disturbing the neck.
That means that I can re-size the long cartridges while assembled, and not cause any damage to the bullet or the neck tension and crimp.
Now I can feel confident that I won't embarrass myself by blowing up an AR15 at the GIRC meeting